Darleen Tana is seeking a judicial review of the Green Party and its co-leaders as the independent MP faces the party-hopping legislation potentially being used against them.
The MP's lawyers have also applied for an interim injunction to stop a Green Party special general meeting from going ahead, where Tana's fate was expected to be decided.
Party co-leader Chlöe Swarbrick revealed the proceedings in a surprise media conference at Parliament, saying it left the party in an "unprecedented" situation.
"At approximately midday today, we received further notice that a hearing has been set down on that interim injunction at 10am tomorrow in the Auckland High Court."
Tana's legal moves are the latest twist in the scandal, which began in March after migrant worker exploitation allegations at their husband's business emerged publicly.
Swarbrick said Tana sought a judicial review of herself, Marama Davidson, and the Green Party. The co-leader added the Greens' lawyer was working pro-bono in the case.
The independent MP faces decision day from the Greens next week. (Source: 1News)
She said: "Throughout this process, we have continued to centre our Green kaupapa. As these proceedings are currently before the court, I will not be able to make any further comments specifically about this case at this time."
Two hundred Green Party delegates were set to vote on Tana's future at a special general meeting on Sunday, after a month of deliberation within the party's membership.
Asked if the latest twist in the saga was disappointing, Swarbrick said: "It is what it is."
SHARE ME